Dear Sonu Kumar Thank you for your guidelines. I will test them. Best regards,Payam Norouzzadeh
On Thu, Mar 8, 2012 at 7:11 AM, Sonu Kumar <1009ukumar at gmail.com> wrote: > On Thu, Mar 8, 2012 at 4:11 AM, Payam Norouzzadeh < > payam.norouzzadeh at gmail.com> wrote: > >> Dear QE users >> >> My system has 54 atoms with a BCC structure. Its primitive unit cell >> includes 27 atoms. >> I am trying to find its lattice constant by using vc-relax. >> After running it several times and for more than 3 weeks still the >> convergence thresholds are not satisfied. >> The forces don't like to get smaller than a specific value (around 0.02). >> Is something wrong with my input file? Please let me know your comments. >> >> Best regards,Payam Norouzzadeh >> >> >> &CONTROL >> title = Eight, >> calculation = "vc-relax", >> restart_mode = 'from_scratch' , >> prefix = "Eight", >> pseudo_dir = "/...", >> wfcdir = '...' , >> outdir = '/...', >> nstep = 100 , >> etot_conv_thr = 1.0E-9 , >> forc_conv_thr = 5.0D-5 , >> max_seconds = 172800 , >> dt = 100 , >> / >> > > force and energy threshold seems to very high, especially > the latter. reduce them. > > >> &SYSTEM >> ibrav = 3, >> celldm(1)=19.622, >> nat = 27, >> ntyp = 3, >> ecutwfc = 70.D0, >> ecutrho = 700.D0, >> occupations='smearing', >> smearing='gaussian', >> degauss=0.02, >> / >> &ELECTRONS >> diagonalization = 'cg', >> conv_thr = 1.D-9, >> mixing_beta = 0.5D0, >> / >> > > use diagonalization= david > > >> &IONS >> ion_dynamics = 'damp' , >> / >> > > use default bfgs algorithm for dynamics > > >> &CELL >> cell_dynamics = 'damp-w', >> / >> > > similarly, use default bfgs. > >> >> > GOOD LUCK !! > > SKumar > IITD > -------------- next part -------------- An HTML attachment was scrubbed... URL: http://www.democritos.it/pipermail/pw_forum/attachments/20120308/8112f4bc/attachment.htm
